How to get this bump shader effect
It may be possible to do it procedurally but here is a way to do it with a normal bake:


Built your pattern, it's like half pyramids that merge each others. Use the Mirror modifier as it's completely symmetrical.





Give your object 2 Array modifiers to make a whole grid. Also add a Subdivision Surface and Shading Smooth it.





Now create a plane, put it above your grid, unwrap and bake the normals.





Use the normal map on the object you want. As your surface seems a bit glossy, mix a Glossy with a Diffuse, and don't forget to plug the Normal map in both these 2 nodes.